Rotation issue

[yuccai]

Hello !

 

There are something i don't understand regarding mesh rotation.

 

1) i find the y positive rotation wrong but maybe it's because the basis is indirect.

2) when i rotate a mesh, does its rotation axis also turn? 

 

Here is an example : http://www.babylonjs.com/playground/#XXH6D#5

There are 4 boxes :

box1.rotation = (0,0,0)

box2.rotation = (0,0,0)

box3.rotation = (PI/2,0,0)

box4.rotation = (PI/2,0,0)

 

in the render loop 

box1.rotation.z += 0.01

box2.rotation.y += 0.01

box3.rotation.z += 0.01

box4.rotation.y += 0.01

 

there is no problem for box1 and box2 (even if i think that box2 should turn in the other way) but box3 and box4 are turning on the same axis in opposite way. I don't understand why.

 

Thank you

 

 

[Wingnut]

No replies from the experts here, yet, yuccai?  hmm.  Well, me posting this worthless reply will bring the issue back to the top of the forum list.  I think boxes 1-3 are acting correctly, but box 4...  phew.  It is acting very strangely, in my opinion.

[yuccai]

Thanks for your reply Wingnut ! It also confirm my doubt

[binyan]

Hi yuccai,

I think you should take a look at this topic (for instance this post). Maybe it would be helpful to you to use 

mesh.rotate(BABYLON.Axis.X , Math.PI/2, BABYLON.Space.WORLD)

 instead of 

mesh.rotation = (Math.PI/2,0,0)

[GameMonetize]

This is all about local against global rotations

https://github.com/BabylonJS/Babylon.js/wiki/How-to-handle-rotations-and-translations

 

By the way to get global rotation, just use mesh.rotate function with BABYLON.Space.WORLD parameter